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Re: Bird Lungs vs. Dinosaur Lungs



Jack wrote:
> 
> On Tue, 18 Nov 1997, Alan Sinder wrote:
> 
> > I'm more interested in how scales could evolve into feathers.
> >
> > - Alan
> >
> > PS  Just because IT seems obvious doesn't make it so.
> >
> 
> The postscript is true.  There has been some question recently about
> whether or not scales actually did give rise to feathers or hair.  Kent
> and Miller. (1997).  _Comparative Anatomy: of the vertebrates._  Wm. C.
> Brown Publishers, Dubuque, discuss the possibility of hair and feathers
> being completely new structures without previous dermal or epidermal
> forms.

That's interesting.  I thought this issue was settled, and had been
settled ever since some experiments on chick embryos demonstrated that
scales and feathers both develop from the mesoderm and you never get
both of them on the same bit of skin.  As far as I know the origin of
mammalian hair is still a mystery, but scales and feathers are
homologous in origin.  Aren't they?

-- JSW